1. Field of the Invention
The present invention relates to a perforator apparatus and a perforating method for photo film, and photo film working/securing apparatus and method. More particularly, the present invention relates to photo film perforating, working, and/or securing apparatus and method of which an operating speed can be heightened.
2. Description Related to the Prior Art
U.S. Pat. No. 4,928,562 (corresponding to JP-A 1-271197) and U.S. Pat. No. 5,461,450 (corresponding to JP-A 6-339898) disclose a perforator apparatus in which continuous material, such as continuous photo film, is provided with perforations of a predetermined pattern. The perforator apparatus includes a punch and a die, which are operated when the continuous photo film is stopped in the course of intermittent conveyance, to form the perforations in the continuous photo film. To convey the continuous photo film to the punch and the die, there are a feed roller and a sprocket roller. The feed roller is arranged upstream from the punch/die set with reference to the conveying direction of the continuous photo film. The sprocket roller is arranged downstream from the punch/die set with reference to the conveying direction. It is also known to use a suction drum instead of the sprocket roller. The feed roller, the sprocket roller and/or the suction drum are driven to rotate by an indexing device.
The perforator apparatus has the single indexing device which is operated for rotating both the feed roller and the sprocket roller. Load of inertia applied to the indexing device is considerably high, so that it is extremely difficult to heighten the speed of the perforator apparatus.
In the perforator apparatus of the prior art, the conveying speed of the feed roller nipping the continuous photo film is determined smaller than the conveying speed of the sprocket roller nipping the continuous photo film downstream therefrom, so as to apply tension to the continuous photo film. The tension causes edges of the perforations of the continuous photo film tightly to contact sprocket teeth of the sprocket roller, to keep the continuous photo film positioned on the punch/die set in an unchanged manner. The precision in the position of forming the perforations is maintained. The continuous photo film receives the tension so high between the sprocket teeth of the sprocket roller and the feed roller, that it is likely that the perforations are damaged by the sprocket teeth of the sprocket roller, and that the continuous photo film is fogged by pressure or scratched by slips of the nip rollers. The nip rollers must be used in a limited condition related to the nipping force.
U.S. Pat. No. 5,461,450 (corresponding to JP-A 6-339898) discloses a method of applying the tension to the continuous photo film by use of suction chambers arranged on upstream and downstream sides of the punch/die set. There is a shortcoming in the perforator apparatus in that a surface of the continuous photo film contacts inner walls of the suction chambers to scratch the surface of the continuous photo film. It is likely that there occurs remarkable shake or undulation of loops of the continuous photo film, due to unfavorable position of the loops.
A photo filmstrip of a 35 mm type consists of a combination of a spool on which the photo filmstrip is wound and a cassette for containing the spool in a rotatable manner. To manufacture the photo filmstrip with the cassettes, a front end or trailer of the photo filmstrip is inserted into a slot formed in the spool, to retain retainer holes of the photo filmstrip on retainer hooks arranged in the slot, so that the front end of the photo filmstrip is secured to the spool. The photo filmstrip includes the sprocket roller, a trimmer unit, a photo film guide and an inserter roller arranged in the order listed. The continuous photo film is cut by the trimmer unit with a cutting operation for forming shapes of the front end and a rear end which is a photo film leader. The front end of the photo filmstrip is moved into the slot of the spool.
JP-A 2-222946 discloses a method in which the photo filmstrip is regularly fed by rotating the sprocket roller, and a photo film path of an air blowing structure is opened after the front end of the photo filmstrip is moved past the inserter roller. When the front end comes near to the spool, the inserter roller is slowed down to an inserting speed, so as to ensure retention of the retainer holes of the front end on the retainer hooks of the spool
To shorten a cycle time of the system of JP-A 2-222946, a conveying speed of the photo filmstrip may be heightened. However this lengthens a distance by which the photo filmstrip is conveyed in a period which starts upon the passage of the front end of the photo filmstrip by the inserter roller and ends upon opening the photo film path. Also it lengthens a distance by which the photo filmstrip is conveyed in a period which starts upon opening the photo film path, and ends upon slowing down the conveying speed to the inserting speed. Consequently a distance between the inserter roller and the spool should be long enough. An insertion guide must be so long that the photo filmstrip is loosened between the inserter roller and the spool. An inserting operation is so unstable that the photo filmstrip is likely to be bent before insertion.